Method and means for translating sounl



July 5, 1932. E. D. PHINNEY 1,865,705

METHOD AND MEANS FOR TRANSLATING SOUND Filed June 26, 1930 2 Sheets-Sheet 1 7'0 REcoRDER 0/? LINE I NVENTOR July 5, 1932 E. 0. PHINNEY 1,865,705

umnon AND mums FOR TRANSLATING sounn Filed June 26. 1930 2 Sheets-Sheet 2 7'0 REcoRaER I NVENTOR it atented daily 5, l32

UNITED STATES PATENT OFFICE EDWARD ID. IPHINNEY, OF iroum VERNON, NEW YORK, ASSIGI Q'OR F ONE-HALF PAUL KOLIBGK, OF NEW YORK, N. Y. Y

METHOD m MEANS FOR TRANSLATIN'G som Application filed June as, mo. Serial F0. 464,080.

This invention relates to sound recording or transmitting and especially to the recording of sound in the production of talking motion pictures.

One of the serious problems encountered during the recording of motion pictures and synchronized sound efiects is the elimination of noise interference originating from sources which are not adapted to be completely si- 1 lenced. For example, one great source of disturbance is [the photo ra hic camera itself, the mechanism of w ic produces dur- -in the operation, a suficient hum or click to e recorded on the accompanyin synchronized sound record in the form 0 an unde} sirable noise. Various attempts have been made in the past to prevent these sounds from reaching the microphone pick-up circuit which ormspart of the sound recording fering efiect has beento place a silencing hood over the working mechanism of the camera or the placingof the camera and the operator "thereof in a sound proof booth. Each of these methods is open to objection; the hood interferes with the operation of the machine and does not com letely muflle the sound, and the placing of t eentiremachine in a sound proof booth is not only an expensive and unwieldy'method but also a hardship on the operator of the camera. Besides, both methods may necessitate photographing through a pane of glass.

--- It is an object of my invention to eliminate a; disturbing sound effects from sounds which it is desired to record or transmit. More specifically,'it is an object of my invention to cause an undesirable sound efiect to be balanced outor ne'utralizedwith respect to a "I translating instrument.

Another object is the provision of a photographic camera and sound recording arrange- 'ment whereby the effect of the camera noise on the recording mechanism is greatly re= 4 'duced, and at the same time to provide means whereby the director of the recording'proc- 'ess may issue verbal orders in an ordinary tone of voice without having his voice re-' corded on the record being produced by the actors under his direction.

system. One manner of reducing the interp In accordance with my invention I provide a sound recording system wherein a plurality of microphone pick-up circuits are utilized in such manner that undesirable sounds are balanced out or neutralized and desired sounds picked up and recorded or otherwise dealt with. I accomplish this result by arranging two or more microphonic pick-up circuits so that a sound from an undesired source acts equally on the two circuits. These two microphonic circuits are in turn connected in op osition with a recording circuit so that i the amplitude of the sound on both of them is equal the result on the recording circuit will be the difference between the two efl'ects or zero. The circuits are also so arranged that the sound from any source which it is desired to record, affects them unequally, the resultant after neutralization being deendentupon the difference in amplitude or strength of the sounds affecting the two microphonic circuits. In carrying out my invention I may place" two pick-up microphones at equal distances from the disturbing sound source, which may be, for example, the photographic camera, and so select the positions of the microphones, camera and desired sound source, e. g. the actors, that the desired sound source is nearer to one of the microphones than to the other. Alternatively, the distance between the microphones and the undesired source and between the microphone and the desired source may be the same and a baflie plate or other suitable means may be provided for causing the amplitude of the'sound from the desired source to effect one microphone circuit more strongly than the other. I

-With such an arrangement as this the two microphones may be placed very close together thereby simplifying the equipment and also rendering it more efiective in neutralizing or'balancing out undesired sounds which come from a variety of sources at different distances from the pick-up means. The distance from the separate mlcrophone pick-ups to the disturbing sound source should preferably be the same so as to insure that the varioussound waves to be cancelled will arrive in the same phase relationship at the neutralizer in order completely to balance out or neutralize each other. When the disturbing sound has some particular frequency as would be the case with a certain type of camera click, the microphones may be placed at unequal distances from the disturbing source and good results secured if each distance is so selected that the sounds arrive in substantially the same phase relationship. In this case as the amplitude of sound varies inversely with the distance from the source,

it will be necessary to adjust the amplification of the separate microphone pick-up circuits so that the two currents to be balanced out will be equal.

The microphones may be displaced either horizontally or vertically depending upon the particular conditions encountered. By displacing the microphones vertically the distance between each of them and any disturbing sources moving on a horizontal plane will remain substantially equal. Whereas if the microphones are displaced horizontally any relative moving of the microphones and the disturbing sound source in a horizontal plane will result in the making of the distance between one microphone and the disturbing sound source diiferent than that of the other microphone and the same sound source.

In order topermit the director of any recording process to give audible directions whatever his position may be with respect to the microphones, a loud speaker and extension mouth-piece or microphone may. be furnished. The loud speaker is then considered as a disturbing sound source and located in a manner similar to that which I have already described in detail. The

mouthpiece or microphone is carried by the director and his orders issued to it at a sound amplitude so low. that the main pick-up microphone circuits are not aflected thereby.

The sound received by the mouthpiece may then be amplified in the usual manner and .45 used to operate the loud speaker which will repeat the order in as loud a tone as desired. With such an arrangement the director is free to walk around as much as he wishes, carrying with him the mouthpiece which is connected to the microphone and loud.

speaker through a flexible cord or other suitable arrangement. If desirable one link in .the connection may be a suitableradio transmitting and receiving system, the sound being converted into radio waves and being transi nitted to a receiving set and where it is utilized in energizing a loud speaker.

The above mentioned and other objects and advantages of my invention and the manner of attaining them will be made clear in the following description and accompanying drawings.

In the drawings, Fig. 1 is a diagrammatic view illustrating one application of my invention.

Fig. 2 is a view showing another arrangement which may be used.

Referring to Fig. 1, reference numerals 1 and 2 indicate pick-up microphones connected respectively to adjustable amplifiers 3 and 4. The output circuits of these amplifiers are connected. to a balancer 5 which serves in any well known manner to transmit to an amplifier 6 the difference between the output currents of amplifiers 3 and 4. This balancer may comprise, for example, three coils mutually coupled, one of them serving as an output coil and the other two being coupled in the opposite sense to amplifiers 3 and 4 respectively so that the magnetic field I line while stillsecuring a good record. For

convenience a circle or other closed figure may be defined on the ground or floor o the studio to indicate the area within which sounds will be properly recorded. As the source of sound 8 is located much nearer to microphone l thanto 2, the amplitude of the output current of output 3 will be much greater than that of 4, therefore the output of balancer 5 will be some appreciable value as it represents the difi'erence between the output'currents of amplifiers 3 and 4. Ourrent from the balancer 5 is fed to the amplifier 6 and then strengthened to the desired value. This current will represent, for the most part, the desired sound efi'ects irom source 8, the sound efi'ects of source 7 being substantially neutralized or cancelled by the balancer, If the source 8 is sufliciently close to microphone 2 to have some eifect on it, this may be reduced by the provision of a sound baflie or filter 9 placed between the source 8 and microphone 2 which acts to cut down the amplitude of the sound from that source reaching the microphone just mentioned. This baflie may be of any suitable material which has the power to prevent the passage of sound without causing harmful reverberations or echos.- This baflie should be so located as to ofier no more im ence to the sound passing between source and microphone 1 than between source 7 and microphone 2. This may be done by placing the bafiie edge wise between the two microphones and pointin in towards source 7, as shown in Fig. 1. 0? course, the bafile may beplaced in a somewhat diflerent position so that the sound path between the source 7 and one of the microphones is less free than that between the source 7 and the other of the microphones, but in thatcase the gain of the microphones 3 and 4 should be so adjusted that their out put currents representing sounds from source 7 are equal.

For permitting audible orders to be given by a director regardless of his position, loud speaker 10 isfurnished. This is treated as a source of undesired sound and located with respect to the pick-up microphones in the same manner as source 7 The output currents of microphones 3 and 4 resulting from sound from loud speaker 10 are balanced out or neutralized in the same manner as currents resulting from the source 7 A mouthpiece or microphone 11 is provided for the director and is connected to the loud speaker through a flexible cable 12 or similar means, which is provided so that the director may carry the mouthpiece and move around without afiecting the position of the loud speaker. ,An

amplifier 13 of any suitable type may be interconnected between the mouthpiece and the loud speaker. If it is not desired to use a cable 12 or if the distance is too great for such uses, a connection between the mouthpiece and loud speaker may be made by radio in any well known manner.

According to the modification as shown in Fig. 2 an additional baflie 14 is provided. Instead of securing equalization of the output currents of the microphones with respect to the sound of source 7 by means of adjustable amplifiers, the bafie 14 might be moved back and forth until equality of the out ut currents of the microphones is secured. y spacing the microphones 1 and 2 apart a relatively great distance as shown in this figure, and placing the camera or other source of undesired sound between them, the efi'ect of the desired sound on the second microphone, 2, is

greatly reduced. As shown in this view the director or his microphone may occupy the position 15, corresponding to that of the camera 7.

Fig. 3 shows the two microphones 1 and 2 mounted very close together. With such an arrangement thebafiie 9 is relied upon to prevent the sound from the desired source 8 from affecting the microphone 2 as strongly as it afi'ects the microphone 1. The camera is arranged to affect both microphones in equal degree. By positioning the various pieces of apparatus in this manner, the distance between the difi'erent sources and each of the microphones need not be considered in determining their output currents; the amplitude of the sound wave from either source would be substantially the same upon arrival at each of the microphones except for the action of bafile 9. Instead of having the baflle, the two microphones may be pointed in opposite directions and placed side by side or back to back as shown in Fig. 4, and the directive efl'ectof the microphones relied upon to create the difierence in the amplitude of the output currents thereof. By placing the mouthpieces of the microphones close together it will be assured that sound will reach the two at substantially the same instant.

Where recording iscarried on indoors, precaution should be taken to prevent harmful reverberations or echoes which would tend to disturb the balance between the pick-up microphone with respect to the disturbing sound source. This may be done by the proper use of draperies or other sound absorbing or retarding devices. This phaseof the recording art is well developed and so further comment with respect to it is not believed to be necessary.

In some cases it may be more convenient to record the outputs of microphones 1 and 2 separately and later combine them into a sin-' gle noise free record. The two records should be combined in such manner that the eifects of the undesired sounds upon the combined output neutralize or balance out. A difierence in phase of the disturbing sounds received by each record may be corrected in the final record merely by causing the record produced by the microphone nearest to the disturbing sound source, to transmit its sound to a pick-up device over an air path or other delay means producing a phase shift equal to that produced by an air path equal to the difference between the distance from the dis turbing sound source and one of the pick-up microphones and the same sound source and the other pick-up microphone. The currents from the pick-up device and currents produced directly from the other record may then be passed through amplifiers similar to 3, 4, and a balancer similar to 5. The output of the balancer will consist of the desired sound free from disturbance due to source 7.

Where the output currents of amplifiers 3 and 4 are unequal a balance in the neutralizer 5 may still be secured by adjusting the neutralizer to be 'afiected by current from one amplifier more strongl than that from the other. If the neutralizer is the three coil transformer type this may be done by making the coupling different between the two primaries and the secondary.

What I claim is:

1. A- .sound translating system comprising in combination, a first microphone circuit for picking up sounds originating at a plurality of separated points, an adjustable amplifier therefor, a second microphone circuit for picking up said sounds, an adjustable amplifier for said second microphone and electrical means for combining the outputs of said amplifiers is opposed relationshi 2. A system according to claim 1 w erein a sound bafile is placed between the microphones of said microphone circuits.

3. A system according to claim 1 wherein a sound baffie is placed between the microphones of the microphone circuits and a separate sound bafile is placed between one of said microphones and one of said separated points.

4. A system according to claim 1 wherein the two microphones are placed side by side pilose together and separated by a soundbaf- 5. Asystem according to claim 1 wherein the two microphones are of the directive type and are faced in different directions to secure a directive efiect.

6. A system according to claim 1 wherein the two micro hones are of the directive type and are face in different directions to secure a directive effect and are placed very close together so that the distance from each of said microphones'to each of said separated points is substantiall the same.

7 A system accor ing to claim 1 wherein the two microphones are placed side b side close together and separated by a soun baffie which is directed toward the source of a sound which it is desired to neutralize.

8. A sound recording system for segregating a sound generated at a first point from sound generated at a second point which comprises,a first sound pick-up device, a second sound pick-up device, said devices being arranged to be affected equally by sound from said second point and unequally by sound from said first point, means for adjustably amplifying the output of said microphonesto different degrees, means for opposing the amplified currents, and means for recording the resultant.

9. The method of segregating sounds emitted from a plurality of separated points which comprises selecting a pair of receivin locations such that sound from an undesire one of said points traverses each location in the same phase relation, and sound from a desired point traverses in substantial volume only one of said locations, intercepting said sounds at said locations, transforming them into electric currents, equalizing the currents correspondin to the undesired sounds and subtracting t e equalized currents of one of said localities from the equalized currents of the other of said localities.

10. The method of recording the performance of an artist, which comprises selecting a pair of receiving locations, causing sounds of said performance to reach said 10- cations at a certain ratio of intensities,.selecting a third location, issuing directin sounds from said third location, causing sai sounds to reach said pair of locations at a different ratio of intensities, translating sounds received at said pairof locations intoelectric currents, separately amplifying'said'currents to such de ees that the components thereof corresponding to sounds from said third.

location are equalized, subtracting one of the amplified currents from the other and utilizing the resultant current.

11. The method of recording the performance of an artist in the presence of an undesired source of noise, which comprises selecting a pair of receiving locations, causing sounds of said performance to reach said locationsat a certain ratio of intensities and sounds from said source of noise to reach said locations at a different ratio, translating sounds received at said locations into electric currents, separately amplifying said currents to such degrees that the components thereof corresponding to sounds from said source of noise are equalized, subtracting one of the amplified currents from the other, and utilizing the resultant current.

12. The method of electrically selecting a desired sound from an undesired sound originatingata distance therefrom which comprises establishing a pair of receiving locations such that the desired sounds reach said locations at a certain ratio of intensities, and

the undesired sounds reach it at a different ratio, translating sounds received at said 10- cations into electric currents, separately amplifying said currents to such degree that the components thereof corresponding to said undesired sounds are equalized, subtracting one of the amplified currents from the other and utilizing the resultant current.

13. In a system for recording the performance of an actor or group of actors, a pair of pick-up microphones and a moving picture camera, said microphones being positioned at the ends of the base of an isosceles triangle, the camera at the apex thereof, the ends of said base being at oints/unequally distant from said actor, an a directing arrangement comprising a loud speaker positioned at the 'apex of an isosceles triangle having the same base as the triangle first mentioned.

14. A system for recording the performance of an actor or group of actors, comprising a p: .ir of pick-up microphones and a moving picture camera, said micro hones be ing positioned at the ends of the ass of an isosceles triangle, the camera and a loud speaker at the apex thereof, the ends of said base being at points unequally distant from said actor, said loud speaker forming, in conjunction with a portable microphone, an amplifier, and means for interconnecting said June, 1930. EDWARD -D. PHINNEY.

microphone and loud speaker, an arrange- 1-20 

